• ETRI Journal
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• v.28 no.5
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• pp.680-683
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• 2006

One objective in developing the next generation of wireless communication systems is to increase data rates and reliability. A promising way to achieve this is to combine multiple-input and multiple-output signal processing with a space-time coding scheme, which offers higher coding and diversity gains and improves the spectrum efficiency and reliability of a wireless communication system. It is noted, however, that time delay differences and phase differences among different channels increase symbol interference and degrade system performance. In this letter, we investigate phase differences and their effects on multiple-input and multiple-output systems, and propose a compensation algorithm for the Rayleigh fading model to minimize their effects.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.6
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• pp.603-607
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• 2008

This paper proposes a fast acquisition method using INS velocity and multiple correlators for high speed vehicles. In order to reduce acquisition time in GPS receiver, the method utilizes inertial velocity information and multiple correlators. Search range of the Doppler frequency is reduced by using INS velocity and the number of cells at one search can be increased by using multiple correlators. By using both multiple correlators and the INS velocity in the acquisition, search space can be greatly reduced. Experimental results show that the method gives faster signal acquisition performance than the conventional method.

• ETRI Journal
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• v.36 no.6
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• pp.953-959
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• 2014

This paper studies the uplink resource allocation for multiple radio access (MRA) in reconfigurable radio systems, where multiple-input and multiple-output (MIMO) multicarrier-code division multiple access (MC-CDMA) and MIMO orthogonal frequency-division multiple access (OFDMA) networks coexist. By assuming multi-radio user equipment with network-guided operation, the optimal resource allocation for MRA is analyzed as a cross-layer optimization framework with and without fairness consideration to maximize the uplink sum-rate capacity. Numerical results reveal that parallel MRA, which uses MC-CDMA and OFDMA networks concurrently, outperforms the performance of each MC-CDMA and OFDMA network by exploiting the multiuser selection diversity.

• Korean Journal of Child Studies
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• v.23 no.4
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• pp.215-226
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• 2002

This study examined the effects of the 'Friends of Nature' education program on multiple intelligence(MI) and emotional intelligence(EI or EQ). The 'Friends of Nature' activity was designed as an education program on the basis of the theories of multiple intelligence and emotional intelligence in order to develop MI and EI through real experiences in the nature. The subjects were 5-year-old kindergarten children, the education activities lasted for 7 months. Significant effects were found in the children's multiple and emotional intelligence between the control group and the activity group in some but not all areas of MI and EI. Consequently, the 'Friends of Nature' program can be said to have partially positive effects on the improvement of children's multiple and emotional intelligence.

• Journal of the Korea Society for Simulation
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• v.6 no.1
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• pp.71-84
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• 1997

For many optimization problems where some of the system components are stochastic, the objective functions cannot be represented analytically. Therefore, modeling by computer simulation is one of the most effective means of studying such complex systems. Many, if not most, simulation optimization problems have multiple aspects. Historically, multiple aspects have been combined ad hoc to form a scalar objective function, usually through a linear combination (weighted sum) of the multiple attributes, or by turning objectives into constraints. The genetic algorithm (GA), however, is readily modified to deal with multiple aspects. In this paper we propose a MAGA (Multiple Aspects-based Genetic Algorithm) as an algorithm for finding the Pareto optimal set. We demonstrate its ability to find and maintain a diverse "Pareto optimal population" on two problems.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1222-1227
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• 2006

These days customers require various things such as multiple train, variable trainset, multiple Auxiliary Power Generator(APG) and so on. Among these, the train with multiple APG is installed with APG in each car. Thus, we control and monitor train installed with multiple APG through the TCMS(Train Control & Monitoring System). The TCMS supervise APG failure status and transmit control data in case of a APG failure or more, so energize or de-energize ESK and LRR. Therefore, we can easily control ESK and LRR which gets hard to control because of multiple APG.

• Journal of electromagnetic engineering and science
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• v.16 no.2
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• pp.126-133
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• 2016

Wireless power transfer (WPT) efficiencies for multiple-input multiple-output (MIMO) systems are formulated with a goal of achieving their maximums using Z matrices. The maximum efficiencies for any arbitrarily given configurations are obtained using optimum loads, which can be determined numerically through adequate optimization procedures in general. For some simpler special cases (single-input single-output, single-input multiple-output, and multiple-input single-output) of the MIMO systems, the efficiencies and optimum loads to maximize them can be obtained using closed-form expressions. These closed-form solutions give us more physical insight into the given WPT problem. These efficiencies are evaluated theoretically based on the presented formulation and also verified with comparisons with circuit- and EM-simulation results. They are shown to lead to a good agreement. This work may be useful for construction of the wireless Internet of Things, especially employed with energy autonomy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.7
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• pp.656-665
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• 1992

In this paper, the performance of the various multiple access techniques for the mobile computer network has been studiedi in the consideration of the charactersitics of the mobile cimmunication channel. In the case of the hidden node occurring. It could be seen that the performance of the code division multiple access (CDMA) technique with simultaneous access function is better than that of the other packet access methods such as carrier sendsed multiple access (CDMA), busy tone multiple access (BTMA) and idle signal multiple access (ISMA) in the view of the throughput and mean delay time. Also, it has been shown that the performance of the CDMA method is superior to that of other packet access techniques such as multiple access (CSMA), etc. when the fading effect or impulsive noise exists in the mobile channel, Especially, in the case of the distributed mobile network it has been shown that the receivertransmitter based CDMA method using the characteristics of CDMA effectively has better throughput and less mean delay time than the commontransmitter based CDMA technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6A
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• pp.494-499
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• 2009

In this paper, we provide an efficient method of user selection for achieving the maximum system throughput in downlink multiuser Multiple-Input Multiple-Output (MIMO) systems. A proposed method is for selecting a fine user set only with powers of each user channel and angles between them. This algorithm is simpler than SUS because there is no considering about the optimal value of correlation. The proposed method finds the user set toward maximizing system throughput, so it has high performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.647-657
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• 1999

An experimental study has been peformed to investigate the heat transfer characteristics of impinging jets with multiple orifice nozzles. Four different shapes of multiple orifice nozzle were tested to improve the heat transfer characteristics of impinging jet. Heat transfer coefficients were obtained by using transient and steady method based on the liquid crystal thermography, and both methods showed very similar results. The effects of multiple orifice nozzles on the heat transfer characteristics of impinging jets were discussed in detail. The results showed that multiple orifice nozzles improved the heat transfer characteristics of impinging jet. Especially, heat transfer coefficients around stagnation region of impinging jets were highly increased.